Re: [PATCH v4 3/3] twist: Add option for selecting twist options for syzkaller's testing

[Dmitry Vyukov]

On Tue, Apr 21, 2020 at 3:22 PM Tetsuo Handa
<penguin-kernel@xxxxxxxxxxxxxxxxxxx> wrote:
>
> When a kernel developer adds a kernel config option, they will not go
> and update configs on all external testing systems. This problem is also
> common for "enable all boot tests that can run on this kernel", or
> "configure a 'standard' debug build". Currently doing these things
> require all of expertise, sacred knowledge, checking all configs
> one-by-one as well as checking every new kernel patch and that needs to
> be done by everybody doing any kernel testing.
>
> In order to reduce the burden of maintaining kernel config options, this
> patch introduces a kernel config option which will select twist options
> when building kernels for syzkaller's testing.
>
> Signed-off-by: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx>
> Signed-off-by: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
> ---
>  lib/Kconfig.twist | 6 ++++++
>  1 file changed, 6 insertions(+)
>
> diff --git a/lib/Kconfig.twist b/lib/Kconfig.twist
> index a1d038bcc2a5..95020a56bbfc 100644
> --- a/lib/Kconfig.twist
> +++ b/lib/Kconfig.twist
> @@ -10,6 +10,12 @@ menuconfig TWIST_KERNEL_BEHAVIOR
>
>  if TWIST_KERNEL_BEHAVIOR
>
> +config TWIST_FOR_SYZKALLER_TESTING


One nice side effect of this is that this can replace
CONFIG_DEBUG_AID_FOR_SYZBOT, which we need to manually bolt and
carefully carry:
https://github.com/google/syzkaller/blob/master/dashboard/config/upstream-kasan.config#L12-L14
Since it's not defined in most kernel trees, any olddefconfig will wipe it out.
Having a config that we can enable that is "officially" in the kernel
will make it much less problematic. Then any custom debugging patches
can use TWIST_FOR_SYZKALLER_TESTING.





> +       bool "Select all twist options suitable for syzkaller testing"
> +       select TWIST_DISABLE_KBD_K_SPEC_HANDLER
> +       help
> +        Say N unless you are building kernels for syzkaller's testing.
> +
>  config TWIST_DISABLE_KBD_K_SPEC_HANDLER
>         bool "Disable k_spec() function in drivers/tty/vt/keyboard.c"
>         help
> --
> 2.18.2
>